Allergies in Cats

If your cat is persistently chewing its feet or scratching at its face, allergy may be a possible cause. Unfortunately, there are no specific signs for allergy so you will need to rely on your pet's veterinarian to make that determination. Allergy diagnosis requires eliminating other causes for your pet's clinical signs. This involves taking a detailed history of your pet's problems, a complete physical examination, and some preliminary laboratory tests. If your pet's history and physical examination suggest that an allergy is likely, your veterinarian may recommend allergy assessment to identify the offending allergens.

The Signs:

The most common sign of cat allergies is itching of the skin; either localized (one area) or generalized (all over the cat). Pets are scratching, face rubbing, biting and chewing at the skin. Usual locations for signs of allergy are the flank, feet, and face, particularly around the eyes, mouth and ears, as well as areas around the base of the tail. Most cats have noticeable hair loss, especially at the tail base in flea allergy. Your cat may have coughing, sneezing, and/or wheezing. Sometimes there may be an associated nasal or ocular (eye) discharge. Some cats have vomiting or diarrhea.

The Causes:

In the allergic state, the immune system "overreacts" to foreign substances (allergens or antigens) to which it is exposed. Allergies occur whenever the offending allergens are present. The more common allergens, such as house dust mites or mold spores, will produce signs of allergy year round, while allergies from plants that pollinate during warm months are apt to cause allergies only when they pollinate. Food allergy may occur by itself or it may be a component of an overall allergy problem. Because of the complexity of allergy diagnosis, the combination of patient history, physical examination, and allergy signs in the pet are all important in making an accurate diagnosis.

  • Flea Allergy

Fleas are one of the most common causes of itchy skin disease in pets. There are two ways fleas can cause a pet to itch. The presence of the fleas crawling around in the fur causes the pet to scratch and bite the skin. Once the pet starts itching, the self-trauma to the skin causes the pet to itch more. If the physical presence of fleas is not enough to make the pet itch, some pets are also allergic to the saliva of the flea. Many pets are extremely sensitive to the saliva from the fleabite although the pet may have little evidence of flea infestation. These animals may develop a condition known as flea allergy dermatitis (FAD). FAD is a very itchy disease and predisposes the pet to secondary bacterial or yeast infections of the skin. Because the pet is so itchy they groom themselves excessively, eliminating any evidence of fleas. A couple of fleabites every two weeks are sufficient to make a sensitive pet very itchy without any physical evidence of fleas. FAD should be considered a progressive disease, with each “flea season” resulting in an increasingly severe reaction in the allergic pet. A well-planned flea control strategy is essential to maintaining the health and comfort of both the pet and the owner. Flea control should be directed at trying to keep fleas off of the pet.

  • Inhalant Allergy

Cats may be allergic to all of the same inhaled allergens that affect people. These include tree pollens, grass pollens, weed pollens, molds, mildew, and the house dust mite. Many of these allergies occur seasonally, such as ragweed, cedar, and grass pollens. However, others are with us all the time, such as molds, mildew, and house dust mites. The cat's reaction, however, usually produces severe, generalized itching. Most cats that have inhalant allergy react to several allergens. If the number is small and they are the seasonal type, itching may last for just a few weeks at a time during one or two periods of the year. If the number of allergens is large or they are present year-round, the cat may itch constantly.

  • Food Allergy

Cats are not likely to be born with food allergies. More commonly, they develop allergies to food products they have eaten for a long time. The allergy most frequently develops in response to the protein component of the food; fish or dairy products are the most common food allergens. Food allergy may produce any of the clinical signs previously discussed, including itching, digestive disorders, and respiratory distress. We recommend testing for food allergy when the clinical signs have been present for several months, when the cat has a poor response to steroids, or when a very young cat itches without other apparent causes of allergy. Testing is done with a special hypoallergenic diet. Because it takes at least eight weeks for all other food products to get out of the system, the cat must eat the special diet exclusively for 8-12 weeks (or more). If positive response occurs, you will be instructed on how to proceed. If the diet is not fed exclusively, it will not be a meaningful test. We cannot overemphasize this. If any types of table food, treats or vitamins are given, these must be discontinued during the testing period.


FLEA PREVENTION - The most important treatment for flea allergy is to get the cat away from all fleas. Therefore, strict flea control is the backbone of successful treatment. There are several medications for getting rid of and keeping fleas off your cat; check with your vet. You should try to keep the cat’s environment as flea-free as possible.

DIETARY SUPPLEMENTS - Fatty Acid supplements are very helpful in decreasing the level of inflammation. Omega 3 fatty acids are most important. Other sources include fish oil and specific veterinary supplements.

ANTIOXIDANTS - Vitamin E and Vitamin C may help.

BATH - (If you can!!) An oatmeal shampoo with cool water will ease the itchiest skin. Leave the shampoo on for 10 minutes then rinse well. With the most severe allergies, bathe your pet twice weekly.

CLEAN ENVIRONMENT - The goal is to eliminate your pet’s exposure to fleas, dust mites, molds, and fungi as much as possible. Environmental controls include frequent vacuuming and mopping all floors, and washing the pet’s bedding. If flea infestation is severe you may need commercial extermination and outdoor spraying every 2-3 weeks. All pets should be removed from premises during environmental treatments.

IMMUNOTHERAPY - In pets with more severe allergies, or in pets where allergies occur year round, specific immunotherapy (allergy shots) may be needed. Your pet's veterinarian will discuss various alternative treatments with you based on your needs and the needs of your pet.

The success of treatment depends on several factors including the overall health of your pet and a commitment to therapy. In general, the steps to successful allergy treatment involve the following: (1) trying to avoid or reduce the allergens in the environment, (2) giving recommended medications to control clinical signs and (3) identifying the specific allergens causing clinical signs in your pet early in disease, followed by allergy immunotherapy. The combination of these therapies will result in successful allergy treatment in the majority of pets.


Lakeside Veterinary clinic assumes no liability for injury to you or your pet incurred by following these descriptions or procedures.